From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by dpdk.org (Postfix) with ESMTP id 3EDBF5A; Fri, 7 Sep 2018 11:30:54 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Sep 2018 02:30:52 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,341,1531810800"; d="scan'208";a="89760058" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.152]) ([10.237.220.152]) by orsmga002.jf.intel.com with ESMTP; 07 Sep 2018 02:30:50 -0700 To: Tiwei Bie , maxime.coquelin@redhat.com, zhihong.wang@intel.com, dev@dpdk.org Cc: seanbh@gmail.com, stable@dpdk.org References: <20180905042852.6212-1-tiwei.bie@intel.com> <20180905042852.6212-2-tiwei.bie@intel.com> From: "Burakov, Anatoly" Message-ID: <9b91d7b1-9f28-069e-af87-8156d5102aed@intel.com> Date: Fri, 7 Sep 2018 10:30:50 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180905042852.6212-2-tiwei.bie@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH 1/3] net/virtio-user: fix deadlock in memory events callback X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 Sep 2018 09:30:55 -0000 On 05-Sep-18 5:28 AM, Tiwei Bie wrote: > Deadlock can occur when allocating memory if a vhost-kernel > based virtio-user device is in use. To fix the deadlock, > we will take memory hotplug lock explicitly in virtio-user > when necessary, and always call the _thread_unsafe memory > functions. > > Bugzilla ID: 81 > Fixes: 12ecb2f63b12 ("net/virtio-user: support memory hotplug") > Cc: stable@dpdk.org > > Reported-by: Seán Harte > Signed-off-by: Tiwei Bie > --- > drivers/net/virtio/virtio_user/vhost_kernel.c | 6 +++++- > .../net/virtio/virtio_user/virtio_user_dev.c | 19 +++++++++++++++++++ > 2 files changed, 24 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c > index b2444096c..897fee0af 100644 > --- a/drivers/net/virtio/virtio_user/vhost_kernel.c > +++ b/drivers/net/virtio/virtio_user/vhost_kernel.c > @@ -115,7 +115,11 @@ prepare_vhost_memory_kernel(void) > wa.region_nr = 0; > wa.vm = vm; > > - if (rte_memseg_contig_walk(add_memory_region, &wa) < 0) { > + /* > + * The memory lock has already been taken by memory subsystem > + * or virtio_user_start_device(). > + */ > + if (rte_memseg_contig_walk_thread_unsafe(add_memory_region, &wa) < 0) { > free(vm); > return NULL; > } > diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c > index 7df600b02..869e96f87 100644 > --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c > +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c > @@ -13,6 +13,8 @@ > #include > #include > > +#include > + > #include "vhost.h" > #include "virtio_user_dev.h" > #include "../virtio_ethdev.h" > @@ -109,9 +111,24 @@ is_vhost_user_by_type(const char *path) > int > virtio_user_start_device(struct virtio_user_dev *dev) > { > + struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config; > uint64_t features; > int ret; > > + /* > + * XXX workaround! > + * > + * We need to make sure that the locks will be > + * taken in the correct order to avoid deadlocks. > + * > + * Before releasing this lock, this thread should > + * not trigger any memory hotplug events. > + * > + * This is a temporary workaround, and should be > + * replaced when we get proper supports from the > + * memory subsystem in the future. > + */ > + rte_rwlock_read_lock(&mcfg->memory_hotplug_lock); > pthread_mutex_lock(&dev->mutex); > > if (is_vhost_user_by_type(dev->path) && dev->vhostfd < 0) > @@ -152,10 +169,12 @@ virtio_user_start_device(struct virtio_user_dev *dev) > > dev->started = true; > pthread_mutex_unlock(&dev->mutex); > + rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock); > > return 0; > error: > pthread_mutex_unlock(&dev->mutex); > + rte_rwlock_read_unlock(&mcfg->memory_hotplug_lock); > /* TODO: free resource here or caller to check */ > return -1; > } > For the memory parts, Reviewed-by: Anatoly Burakov -- Thanks, Anatoly